Waste products, including those waste products resulting from the preparation of food in restaurants, are frequently flushed down a drain pipe with water. Such restaurants typically collect much of these waste products in a trap intended to prevent the waste products from passing directly into a public sewage system. These accumulated waste products have been collected from the restaurant by service vehicles equipped with vacuum systems. U.S. Pat. No. 4,816,167 to Vanderslice for a Portable System For Dewatering Contents Of Sanitary Sewer Traps teaches a system for processing such waste products. The teachings of U.S. Pat. No. 4,816,167 are incorporated herein by reference. The present invention provides an improved apparatus and method directed to collecting the waste, dewatering the solids, returning the cleaned water to the sewage system and disposing of the solid residue.
The Vanderslice patent teaches, as a first step, the practice of collecting the water-carried waste in a first compartment of a tank so that a portion of the solids sinks to the bottom of the tank. Next, the tank is tilted to move the solids to a remote section of the tank, and much of the water is removed to a second compartment by means of a pressure or vacuum applied through a transfer pipe. The second compartment is separated into sub-compartments by internal walls which each have a baffle tube connecting a prior sub-compartment to a latter sub-compartment to flow water at a selected height above the tank bottom so as to further separate the solids from the water. The separation is assisted by the addition of alum to the dirty water to promote the precipitation of solids, especially grease.
A drawback to the Vanderslice apparatus and method is that the water does not separate sufficiently from the solids to allow the residual water to be returned to the sewer system for conventional processing. A further drawback is that solids residue accumulates in the sub-compartments which require frequent cleaning. An additional drawback of the previous system is that the tank has to be cleaned at a special facility and can not be operated for a long period between such cleanings.
It is therefore an object of this invention to provide an apparatus and method for the collection and dewatering of waste products which causes the solids to be thoroughly separated from the water.
It is a further object of this invention to provide an apparatus and method for the collection and dewatering of waste which use results in producing water which has been sufficiently separated and cleaned so that the water may be reintroduced to the sanitary sewer lines.
It is an additional object of this invention to provide an apparatus and method for the collection and dewatering of waste which will allow long periods of operation between required cleaning of the interior of the tank.
Other objects and advantages will be more fully apparent from the following disclosure and appended claims.